äidinkielensä

äidinkielensä is the third-person possessive form of the Finnish noun äidinkieli, meaning “one’s mother tongue” or “native language.” The term denotes the language a person learned in early childhood and uses as their primary language at home and in daily life. It is commonly employed in sociolinguistic discussion and in population data to describe an individual’s language background and cultural identity.

Morphology and usage help explain the form. The base äidinkieli gains the possessive suffix -nsä (or -nsa, depending on vowel harmony), yielding äidinkielensä for “his/her mother tongue.” The form is used when referring to someone’s language without repeating the person’s name, for example: Hänellä on hyvä hallinta äidinkielestään, or Hänen äidinkielensä on suomi, meaning “His/her mother tongue is Finnish.”

In practical terms, äidinkielensä is often contrasted with other language terms in Finnish discourse. It relates to the concepts of toinen kieli (second language), vieras kieli (foreign language), or kielen oppiminen later in life. In statistics and education, äidinkieli or äidinkielensä captures what language people learned first and use most at home, informing policy on language instruction, bilingual education, and cultural heritage.

See also: äidinkieli, language and identity, bilingualism. Note that while äidinkielensä emphasizes possession by a specific individual, the broader concept of “mother tongue” encompasses personal, social, and cultural associations tied to one’s primary language.